Corrugated plastic pipe sections having flanged ends and structurally tight joints thereof

ABSTRACT

Corrugated plastic pipe sections having a flanged end formed by a circumferential portion of an end corrugation or section of the pipe liner and a method and kit for joining flanged end corrugated plastic pipe sections are described in a system in which a portion of the end currugation or pipe liner forms a flange and a peripheral flange clamp straddles flanges and draws the flanges together to provide a structurally sound joint. A gasket may be interposed between flanges or the flange periphery and the clamp. The invention achieves a cost effective tight joint, allows field cuts of the corrugated plastic pipe and the fabrication of fittings from corrugated pipe sections and provides a selectable pipe size reducer coupling for corrugated plastic pipe.

TECHNICAL FIELD

[0001] This invention relates to corrugated polyethylene pipes and ajoint system therefor for larger diameter pipes (greater than 2 inchdiameter). The invention provides a robust and cost effectivemechanically secure and water tight joint, depending on configurationand application, that reduces infiltration and ex-filtration in aninstalled pipe system. The invention overcomes hydraulic effects andground shift short falls encountered in present PVC, concrete, and HDPEpipe systems that result in the separation and/or misalignment of belland spigot joints, causing the joints to leak, excessive infiltrationand tree/plant root penetration into sanitary sewer and septic systems,especially in the lateral lines, and infiltration and ex-filtration inhighway drainage systems. The joining system of the invention is adaptedto High Density Polyethylene (HDPE) pipe and provides chemicalresistance to sewer gases, animal and industrial waste, and provides thecapability of longer and variable pipe lengths that decrease the numberof joints per line. The invention expands the utility of HDPE pipe indrainage, agriculture, highway, sanitary sewer, waste water reuse,irrigation, industrial waste, animal waste, fiber optics, and utilitycable applications.

BACKGROUND ART

[0002] Large diameter corrugated plastic pipe sections (typically formedfrom polyethylene) are known products. Past and present attempts todesign water tight joints for corrugated plastic pipe to expand the useof the pipe to drainage and sanitary sewer applications typicallyinvolve radial compression of a gasket (molded or extruded and spliced)that occurs when an end section of the pipe formed as a spigot isinserted into a corresponding end section of a pipe formed into a bell.Pushing a spigot, with a gasket wrapped around its exterior cylindricalsurface, into a bell having a tapered internal surface and interferencefit, typically provides the radial compression of the gasket. The motionof pushing the gasket on the spigot in an axial direction and thefrictional force on the interior lateral surface of the bell may causethe gasket to un-seat, twist and roll. In addition, circumferentialtensile stresses on the interior of the bell, required to maintaingasket compression, decrease the stress crack resistance of the plasticpipe. A gasket is typically located in either a groove on the crest orcrown or in the root of a corrugation near the pipe end of the pipesection. In the prior case the stiffness of the corrugation is notsufficient to withstand the hydrostatic water pressure required toprevent water leaks. As a result the corrugations supporting the groovethat locates the gasket are sometimes made stronger by injecting rigidfoam inside the corrugation. The latter case requires banding or otherstrengthening to avoid the large stresses that cause stress cracking.Both solutions add considerable cost to obtain a reliable water tightjoint. Bell and spigot joints rely on the compression of a radial gasketand have the additional disadvantage that internal pressure acts on theaxial projected area of the wetted portion of the gasket causing a“hydraulic effect” that acts to open the joint.

[0003] A further disadvantage of joints that utilize radial compressedgaskets is that the joints are subject to failure, leaking water underpressure, as a result of rolling and twisting of the gasket, or bystress cracking of the bell. William C. Andrick in U.S. Pat. No.5,687,976 describes a symmetrical gasket for pipe joints that sealsagainst both internal lateral surface of a bell and external lateralsurface of a pipe having transverse corrugations. James B. Goddard inU.S. Pat. No. 5,765,880 discloses a bell and spigot joint for helicaldouble wall corrugated pipe. Kenichi Hattori in U.S. Pat. No. 4,871,198discloses a clamp type corrugated plastic pipe coupling in which arubber gasket is utilized in radial compression to seal the joint. Inthe latter case, the metal clamp reduces the stress-cracking problem.However, the gasket transfers stress to the plastic inner wall or linerand to the corrugations. Both the corrugations and the liner arerelatively low in stiffness and have difficulty maintaining the radialcompression of the gasket. The high creep behavior of semi-crystallinepolymers such as high-density polyethylene is responsible for increasedleaking due to aging. It may also be difficult to assemble a joint asdescribed by Hattori when the pipe sections to be joined are located inan open trench. Another disadvantage is the relatively high costassociated with an extended cylindrical gasket and a metal clamp. Belland spigot type joints have an additional disadvantage insofar as fieldcuts of sections of corrugated pipe are not possible.

[0004] My co-pending applications for patent in the United States Patentand Trademark Office, “Joint and Seal for Large Diameter CorrugatedPlastic Pipe and Method for Joining Plastic Pipe Sections,” Ser. No.09/597,338 filed on Jun. 19, 2000; “Water tight Joint and Method ofSealing Drainage and Sanitary Sewer Pipe Sections,” Ser. No. 09/788,913filed on Feb. 19, 2001; and “Method and Joint Design for Infield WaterTight Sealing of Dual Wall Corrugated Plastic Pipe Sections,” Ser. No.091794,638 filed on Feb. 27, 2001 detail the characteristics andproperties of corrugated polyethylene/plastic pipe and problemsencountered by the prior art in attempting to effect a water tight sealbetween adjacent pipe sections. In my co-pending applications forpatent, I disclose, inter alia, a method and design that avoids both therolling of the gasket and stress cracking by utilizing a portion of theend corrugation to provide a means for self-energizing a water tightseal for joining two abutting sections of pipe. The present inventionreduces the cost and complexity of producing secure tight joints in HDPEcorrugated pipe.

[0005] Typically, soil tight performance in corrugated plastic drainagepipe is obtained by a compressing a gasket having a relatively smallcross section when compared to the height and longitudinal width of atransverse corrugation. A transverse ridge at the crown of the endcorrugation (referred to as a spigot) typically supports a joint gasket.The locating seat (transverse ridge) on the end corrugation has adisadvantage in that formation of the spigot requires a thermoformingmold to be introduced in the corrugation process and the other end ofthe corrugated plastic pipe either requires a molded bell at the end ornecessitates the use of a dual bell coupler. This approach suffers fromthe weakness of the walls the corrugation supporting the crown of thecorrugation and the gasket plus the cost associated with manufacturingin-line bell and spigot couplers. The present invention has theadvantages of eliminating the requirement to introduce a bell and spigotmold pair that avoids the cost of the bell and spigot mold and ofincreasing the production rate of the pipe by removing the need toreduce production rates while forming of the bell and spigot.

[0006] The majority of existing drainage and sanitary sewer systemsutilize reinforced concrete, polyvinyl chloride (PVC) and corrugatedpolyethylene pipe having bell and spigot joining systems. The bell andspigot joining systems typically function by radial compression of aperipheral gasket located between mating bell and spigot. When properlymated bell and spigot gasket systems provide some protection againstinfiltration and ex-filtration. However, shifts in the soil, changes insoil conditions, and seismic occurrences cause the bell and spigotjoints to misalign and/or open sufficiently, causing infiltration underwet conditions and ex-filtration under dry conditions. Infiltration isresponsible for tree root penetration that causes blockage. Postinstallation, bell and spigot joining systems have the disadvantage ofinternal hydraulic pressure exerting forces on the wetted projected areaof the radially compressed gasket, separating the pipe ends. Thesefactors are responsible for infiltration and ex-filtration causingexcessive wastewater treatment costs and pollution of our nationalwaterways respectively. The invention advantageously supplies a rigidjoining system for corrugated plastic pipes resulting in rigid joints inchemically resistant flexible pipes capable of accommodating shift inthe soil and/or back fill without breakage in the pipes or the joints.

DISCLOSURE OF THE INVENTION

[0007] The invention comprises corrugated plastic pipe sections having aflanged end formed by a circumferential portion of an end corrugation orthe pipe liner and a method and kit for joining corrugated plastic pipesections to create a structurally sound joint that may be adapted forapplications where soil and water tight joint properties are required.In the system of the invention, a portion of the end corrugation or pipeliner forms a flange at the end of each pipe to be joined; a clampstraddles the outside lateral surfaces of the two flanges and draws theflanges together. A joint is thereby formed. An annular elastomericgasket may be inserted contacting the facing surfaces of the pipe flangeand a second flange at the end of another pipe or fitting, or theradially peripheral side edges of the flanges. The invention achieves acost effective structurally sound joint, allows field cuts of thecorrugated plastic pipe and the fabrication of pipe fittings andconnectors from corrugated pipe sections with limited modification tothe molding process.

[0008] An object of the invention is to provide a tight joint byproviding a flange at the end of the corrugated plastic pipe from acircumferential portion of the end corrugation, thereby avoiding theneed and expense associated with molding separate bell and spigot ordual bell couplers. It is a further object of the invention to provide asection of corrugated plastic pipe having a flange at its end formedfrom a section of a corrugation, the liner and/or from both the linerand the corrugation. It is also an object of this invention to provide asection of corrugated plastic pipe joined to an abutting section ofcorrugated plastic pipe or a fitting having a flange at its end byinserting a gasket between the abutting flanges and utilizing a clamp toaxially compress a gasket to form a water tight seal. An external rigidclamp supports the relatively weak flange eliminating the need tostiffen the end of the corrugated pipe by injecting rigid foam into theend corrugations.

[0009] The external rigid clamp acts as a rigid coupler that prohibitspost installation separation of the joined pipe ends caused by groundshifts, changes in soil conditions and seismic occurrences. Thisinvention prevents infiltration, ex-filtration and pipe separation byrigidly coupling the pipe ends by applying an external rigid flangeclamp that axially compresses the gasket by applying pressure to theflange at the end of the corrugated plastic pipe from a circumferentialportion of the end corrugation.

[0010] Once pipe ends are locked together the pipe must be compliant toprevent fracture of the pipe when the earth shifts; if the pipe ends arenot locked together, they misalign and/or separate. Because PVC andconcrete pipes are rigid, the bell and spigot joints accommodate theground shifting by joint misalignment and potential separation. As aresult, pipe integrity is sacrificed for joint integrity. The inventioncomprises a rigid joining system for corrugated plastic pipes in whichthe joint provides a permanent rigid fixation between adjacent pipesections and, over the run of a pipe line, provides sufficientflexibility to accommodate ground shifts. At present, the corrugatedplastic pipe industry utilizes bell and spigot and welded joiningsystems. In the former case, ground shifts and hydraulic effectscompromise joint integrity; in the latter case, the costs of welding areprohibitive.

[0011] The present application also discloses a kit for providing awater tight seal between adjacent (abutting) sections of corrugatedplastic pipe or fittings comprising a gasket and a flange clamp adaptedto form the joint. In a further object, the invention comprises a designfor and method of using fabricated fittings to join flanges on the endsections of corrugated pipe that are formed from circumferentialportions of the pipe corrugations and/or liner. Presently fabricatedfittings typically require pipe ends that have bell shapes or spigotshapes and may require dual bell couplers. The present inventioneliminates the need for specially formed ends and couplings and allowscorrugated pipe to be manufactured without introducing coupling moldsinto the forming process, thus saving the money associated withutilizing specially molded bells and spigots for fittings. The inventioneliminates the need for bell and spigot ends on sections of corrugatedplastic pipe and fittings and eliminates the need for internal andexternal dual bell couplers.

[0012] Presently stepped reducing “Y”, “T” and four way fittings arefabricated for single wall corrugated pipe. This has been accomplishedby roto-molding and by blow molding fittings with several diameter bellsin series. This practice allows the pipe manufacturer to supply auniversal fitting that is adapted in the field by the installingcontractor, who simply cuts off the fitting at the bell diameter of hischoice. It is a further object of this invention to disclose steppedfittings for dual wall corrugated plastic pipe that utilize flanges ofvarying diameters. This invention discloses a molded, stepped,selectable diameter, and offset reducer coupling that provides a meansof forming a water tight joint with corrugated plastic pipe and plasticand none plastic pipe sections having different diameters and flangeends. Furthermore it is the object of this invention to disclose amolded fitting design with an integral stepped, selectable diameter, andoffset reducer coupling for joining corrugated plastic pipe havingflange ends and the same and different diameters in a water tightfashion.

[0013] The enhanced joint design and method of fabricating soil tightand water tight joints disclosed is cost effective, allows field cuts ofcorrugated plastic pipe, and simplifies in-plant fabrication of flangedend fittings from sections of corrugated pipe. A clamp is utilized tocompress the annular gasket by drawing the two flanges together. Thisinvention utilizes a portion of the end corrugation or liner to providean interior surface to compress a rubber gasket and an exterior surfaceagainst which the clamp radially pushes inwardly.

[0014] A further object of the invention is to offer a solution toenvironmental protection and pollution containment issues. The inventionis directed to the subject of an enhanced water tight joining system forcorrugated plastic pipe that rigidly couples pipe end having a flangeformed by the end corrugation inserting a gasket and applying a flangeclamp and addresses, inter alia, the problems identified below thatadversely affect the environment:

[0015] The Fact Sheet presented at the 1995 Navy Pollution PreventionConference On The Investigation and Rehabilitation of Sewer Systems byEllen K. Brown of the Engineering Field Activity Northwest of the NavalFacilities Engineering Command, states “When a sewer system is brandnew, it is fairly tight against extraneous infiltration and inflow, butnot perfectly so. Even new systems experience a 5% increase in flowsduring wet weather. Over time, many biological, chemical and physicalforces act on the sewer pipes to reduce their integrity. In activeseismic zones, ground shifts can cause pipes to become misaligned,opening gaps at joints or causing breaks. Construction activity abovethe line can have similar effects. Underground springs can undermine thepipe allowing it to sag and open joints. Hydrogen sulfide produced inthe sewer can eat away the crown of concrete pipe. Root intrusion atjoints and cracks can wedge open pipelines. Poorly made lateralconnections can weaken a pipe or leave a gap around the connection.”

[0016] Infiltration and ex-filtration in drainage pipe systems caused byleaky joint systems contribute to increased cost of water treatment andcontamination respectively. “The Uniteds States Environmental ProtectionAgency (2000) identified sediment as the most widespread pollutant inthe Nation's rivers and streams, in that sediment affects aquatichabitat, drinking water and treatment processes and recreational uses ofrivers, lakes and estuaries.” A Synopsis of Technical Issues forMonitoring Sediment in Highway and Urban Runoff by Gardner C. Bent, JohnR. Gray, Kirk P. Smith and G. Douglas Glysson, Open-File Report 00-497prepared in cooperation with the Federal Highway Administration, U.S.Department of the Interior, U.S. Geological Survey.

[0017] The system of the invention is intended to reduce the occurrenceand severity of these problems and to provide joints for corrugatedplastic pipes meeting the following specifications: ASTM-D 3212-96a,Standard Specification for Joints for Drain and Sewer Plastic PipesUsing Flexible Elastomeric Seals, 10.8 psi for 10 minutes, with ananticipated performance of >30 psi continuous & structural; ASTM-C443-01, Standard Specification for Joints for Circular Concrete Sewerand Culvert Pipe, Using Rubber Gaskets, 13 psi for 10 minutes within 24hours, moisture or beads of water acceptable, with an anticipatedperformance of >30 psi continuous, zero leakage; and to provideperformance improvements over concrete pipe systems covered by ASTM-C1103-94, Standard Practice for Joint Acceptance Testing of InstalledPrecast Concrete Pipe Sewer Lines, 3.5 psi with <1 psi drop in 5seconds, with an anticipated performance of 0 psi drop; ASTM-C 969-94,Standard Practice for Infiltration and Exfiltration Acceptance Testingof Installed Precast Concrete Pipe Sewer Lines, 200 gal./in. (ofinternal diameter) (mile of sewer) (24 h), with an anticipatedperformance of zero leakage; ASTM-C 118-99, Standard Specification forConcrete Pipe for Irrigation or Drainage, 10 psi for 10 minutes withoutexcessive leakage through wall of the pipe and transient ˜50 psi withoutcracking through pipe wall, with an anticipated performance of >40 psicontinuous.

[0018] In brief, it is an object of the invention to provide a systemfor corrugated HDPE pipe useful in the sanitary sewer and drainagemarkets currently serviced by the concrete and PVC pipe industries,providing product differentiation, lower production costs and highermargins by one product offering zero in and zero out rigid joiningsystems that maintain joint alignment and prevent pipe separationbetween corrugated HDPE pipe sections. The joint system along the lengthof the pipe line allows sufficient flexibility to accommodate postinstallation ground shifts. As measured on the total cost of waste watertreatment—instead of pipe and installation cost—the corrugated HDPE pipejoint system provides a major over all cost advantage over concrete andPVC sanitary sewer pipe as viewed by county and municipality engineersresponsible for total operating costs. As a low cost drainage pipeproviding zero in and zero out performance, the corrugated HDPE pipesystem will contribute to reducing sedimentation of highway runoff thatis identified by EPA and other organizations as the principal cause ofcontamination of the nation's waterways. Use of the system of theinvention will open the use of corrugated HDPE pipe in new markets suchas waste water reuse, irrigation, industrial waste, animal waste, fiberoptics, and utility cables.

[0019] To the extent that existing pipe systems utilized in drainage andsanitary sewer applications allow infiltration under wet conditions andexfiltration under dry conditions resulting in excessive waste watertreatment costs and pollution of our national waterways caused by leakypipes and joining systems, the invention provides a robust costeffective pipe and joining system providing zero in and out performance,flexibility along an extended pipe length with a secure and reliablemechanism for the mechanical connection of pipe sections.

[0020] The invention is described more fully in the followingdescription of the preferred embodiment considered in view of thedrawings in which:

BRIEF DESCRIPTION OF DRAWINGS

[0021]FIG. 1 is a cross section of two sections of dual wall corrugatedplastic pipe having flanges at their ends formed from a section of thecircumferential portion of an end corrugation.

[0022]FIG. 2 is a cross section of two sections of single wallcorrugated plastic pipe having flanges at their ends formed from thecircumferential portion of an end corrugation segment.

[0023]FIG. 3 is a cross section of two sections of dual wall corrugatedplastic pipe having flanges at their ends formed from a circumferentialportion of the inner wall or liner extending from the end.

[0024]FIG. 4 is a cross section of two sections of dual wall corrugatedplastic pipe having flanges at their ends formed from a circumferentialportion of the inner wall or liner and a section of (namely, a partialsegment of material) what would otherwise form an end corrugation.

[0025]FIG. 5A is a cross section of a joint between abutting ends of twosections of dual wall corrugated plastic pipe utilizing a wedge shapedgasket between the abutting ends and a circumferential or perimeterflange clamp.

[0026]FIG. 5B is a cross section of a joint between abutting ends of twosections of dual wall corrugated plastic pipe utilizing an “O” ringgasket between the abutting ends and a flange clamp.

[0027]FIG. 5C is a cross section of a joint between abutting ends of asection of dual wall corrugated plastic pipe and a section of rigid pipehaving a flange end utilizing a flat gasket between the abutting endsand a perimeter flange clamp.

[0028]FIG. 5D is a cross section of a concrete pipe with a mortaredmetal flange joined to a corrugated plastic pipe utilizing a gasket anda flange clamp.

[0029]FIG. 5E is a cross section of a joint between abutting ends of twosections of dual wall corrugated plastic pipe utilizing an “O” ringgasket and an inverted wedge shaped flange clamp.

[0030]FIG. 6A shows a cross section of a joint between two sections ofcorrugated plastic pipe having flange ends, utilizing an external gasketthat straddles the abutting flanges and a circumferential or perimeterflange clamp having split annular plates.

[0031]FIG. 6B shows a cross section of a joint between two sections ofcorrugated plastic pipe having flange ends, utilizing an internal gasketbetween the abutting flanges and a flange clamp having a pair of splitannular plates.

[0032]FIG. 7A shows the front view of a flat gasket utilized betweenflanges. and FIG. 7B shows the side view of the gasket.

[0033]FIG. 7C shows the front view of a wedged gasket between flangesand FIG. 7D shows the side view of the gasket.

[0034]FIGS. 7E and FIG. 7F respectively show the front and side views ofan “O” ring gasket between flanges.

[0035]FIG. 7G and FIG. 7H respectively show the front and side views ofan external inverted “V” gasket.

[0036]FIG. 8A and FIG. 8B respectively show the front and side views ofa typical single element “V retainer circular” flange clamp utilized todraw the flanges together and compress the gasket.

[0037]FIG. 8C and FIG. 8D respectively show the front and side views ofa typical three-segment “V retainer” circular flange clamp utilized todraw the flanges together and compress the gasket.

[0038]FIG. 8E and FIG. 8F respectively show the front and side views ofa typical three-segment “inverted wedge” circular flange clamp utilizedto draw the flanges together and compress the gasket.

[0039]FIG. 8G and FIG. 8H respectively show front and side views of ajoint utilizing a lever or toggle clamp.

[0040]FIGS. 8I and 8J respectively show top and front views of acircular flange clamp having a ratchet mechanism for locking in thetightened configuration and tool for tightening the circular flangeclamp.

[0041]FIG. 9A and FIG. 9B respectively show the front and side views ofa circular flange clamp having two spilt plates.

[0042]FIG. 10A is cross sectional view of adjacent ends of dual wallcorrugated plastic pipe sections having end flanges formed fromcircumferential portions of end corrugations.

[0043]FIG. 10B is a cross sectional view of two end sections of dualwall corrugated plastic pipe, a wedged shaped gasket and a circularflange clamp before final assembly.

[0044]FIG. 10C is a cross sectional view of a section of an assembledsoil tight and water tight joint composed of two flange ends of dualwall corrugated plastic pipe, a wedged shaped gasket and circular flangeclamp.

[0045]FIG. 10D is a cross sectional view of adjacent ends of dual wallcorrugated plastic pipe sections having flanges formed fromcircumferential portions of end corrugations showing the preferredembodiment.

[0046]FIG. 10E is a cross sectional view of two end sections of dualwall corrugated plastic pipe, a wedged shaped gasket formed to match theinternal surface of the end corrugations and a circular flange clampbefore final assembly showing the preferred embodiment.

[0047]FIG. 10F is a cross sectional view of a section of an assembledsoil tight and water tight joint composed of two flanged ends of dualcorrugated plastic pipe, a wedged shaped gasket formed to match theinternal surface of the end corrugations and circular flange clampshowing the preferred embodiment.

[0048]FIG. 10G is a cross sectional view of adjacent ends of dual wallcorrugated plastic pipe sections having flanges formed fromcircumferential portions of end corrugations, wedged shaped gasketformed to match the internal surface of the end corrugations and belland spigot flange clamp.

[0049]FIG. 10H is a cross sectional view of two end sections of dualwall corrugated plastic pipe, a wedged shaped gasket formed to match theinternal surface of the end corrugations, bell and spigot flange clampbefore final assembly.

[0050]FIG. 10I is a cross sectional view of a section of an assembledsoil tight and water tight joint composed of two flanged ends of dualcorrugated plastic pipe, a wedged shaped gasket formed to match theinternal surface of the end corrugations and bell and spigot flangeclamp.

[0051]FIG. 11A is cross sectional view of two end sections of singlewall corrugated plastic pipe in which a flange is formed from acircumferential portion of the end corrugations.

[0052]FIG. 11B is a cross sectional view of two end sections of singlewall corrugated plastic pipe, a flat gasket and a circular flange clampbefore final assembly of a joint.

[0053]FIG. 11C is a cross sectional view of a section of an assembledsoil tight and water tight joint composed of two flange ends of singlewall corrugated plastic pipe, a flat gasket and a circular flange clamp.

[0054]FIG. 12A shows a cross sectional view of two end sections ofadjacent dual wall corrugated plastic pipes in which a flange is formedfrom the liner at the pipe end.

[0055]FIG. 12B is a cross sectional view of sections of the ends of twodual wall corrugated plastic pipes with flanges formed from the liner atthe pipe ends, a flat gasket and a circular flange clamp before finalassembly of a joint.

[0056]FIG. 12C is a cross sectional view of a section of an assembledjoint composed of two ends of adjacent dual wall corrugated plasticpipes having flanges formed from the liner of the pipes at the pipeends, a flat gasket and a circular flange clamp.

[0057]FIG. 13A is cross sectional view of sections of two ends of dualwall corrugated plastic pipes having end flanges formed from a portionof the end corrugation and the liner at the pipe end.

[0058]FIG. 13B is a cross sectional view of sections of two ends of dualwall corrugated plastic pipes in which a flange is formed from a portionof the end corrugation and the liner at the pipe end, a flat gasket anda circular flange clamp before final assembly of a joint.

[0059]FIG. 13C is a cross sectional view of a section of an assembledjoint composed of two ends of dual wall corrugated plastic pipe in whicha flange is formed from a portion of an end corrugation and the liner atthe pipe end, a flat gasket and a circular flange clamp.

[0060]FIG. 14A is cross sectional view of sections of two ends of dualwall corrugated plastic pipe having a flange formed from acircumferential portion of the end corrugations.

[0061]FIG. 14B is a cross sectional view of two sections of ends of dualwall corrugated plastic pipe, an “O” ring gasket and a circular flangeclamp before final assembly of a joint.

[0062]FIG. 14C is a cross sectional view of a section of an assembledjoint composed of two flange ends of dual wall corrugated plastic pipe,an “O” ring gasket and a circular flange clamp.

[0063]FIG. 15A is cross sectional view of sections of two ends of dualwall corrugated plastic pipe in which a flange is formed from acircumferential portion of the end corrugations of the respective pipes.

[0064]FIG. 15B is a cross sectional view of two sections of ends of dualwall corrugated plastic pipe, an external inverted “V” gasket and acircular flange clamp before final assembly of a joint.

[0065]FIG. 15C is a cross sectional view of a section of an assembledjoint composed of two flange ends of dual wall corrugated plastic pipe,an external inverted “V” gasket and a circular flange clamp.

[0066]FIG. 16A is a cross sectional view of a dual wall corrugatedplastic “Y” fabricated fitting with end flanges joined to sections ofdual wall corrugated polyethylene pipe having corresponding end flanges.

[0067]FIGS. 16B and 16C respectively show the front and end views of anassembly of a molded stepped reducing “T” fitting joining two in-linepipe sections of dual wall corrugated plastic pipe to a smaller diameterdual wall corrugated plastic pipe.

[0068]FIGS. 16D and 16E respectively show the front and end views of anassembly of a fabricated “T” fitting joining two in-line pipe sectionsof dual wall corrugated plastic pipe to smaller diameter dual wallcorrugated plastic pipe by means of a molded stepped reducer.

[0069]FIG. 17 shows a front view of a kit for providing a water tightseal including a gasket and a circular flange clamp for forming thejoint and seal, and two pipe sections having end flanges with which thekit is used.

[0070]FIG. 18 shows a front view of a kit for providing a water tightseal between corrugated plastic pipe sections including a gasket, acircular flange clamp, a router, and a router guide for forming theflange at the end of the respective two pipe sections to be joined attheir end flanges.

[0071]FIG. 19 shows a structural joint formed by pipe or fitting endflanges and clamp without a gasket between the facing flanges.

[0072]FIG. 20A is a side view of a joint applied to a non-circular,oblong, oval elliptical or other curvilinear perimeter pipe.

[0073]FIG. 20B is a radial cross section of the joint of FIG. 20A alsoshowing a single sectioned toggle clamp.

BEST MODE FOR CARRYING OUT THE INVENTION

[0074] The invention facilitates the field installation of structural,soil tight and water tight joints between sections of single andmultiple wall corrugated plastic pipe utilized for drainage and sanitarysewer applications. The invention provides a section of corrugatedplastic pipe having a flange at its end formed from the circumferentialportion of a corrugation segment and/or the pipe liner. In its differentaspects and embodiments, the invention comprises a section of a plasticpipe, or fittings for plastic pipe, having transverse corrugations andan end flange maintained in a joint relationship by a peripheral clamp.

[0075] The invention produces joints between pipes and a pipe andfitting have tightness properties ranging from a structurally sound,tight joint effected by the use of a clamp only (without a gasket) withregard to a flanged end, ranging to soil tight, water tight and gastight joints depending on flange, gasket and clamp design parameters toadapt the joint system for a predetermined use or environment. Acircumferential portion of a corrugation or a circumferential portion ofthe liner extending from the corrugated pipe section forms the flange.In an assembly, two abutting sections of corrugated plastic pipe havingflanges on their ends are joined together in an assembly in which aperipheral flange clamp engages the flanged ends forming a structuraljoint.

[0076] A gasket may be interposed between the flanges. The gasket mayhave a flat annular shape, a wedge shaped cross section, or an “O” ringshaped cross section and may include other shapes such as ridges and thelike on the surface thereon. In the invention, a section of corrugatedplastic pipe having a flange may be joined to any section of acomplementary pipe or fitting having a flange. The circular flange clampmay be a “V” (or “U” shape) groove or channel single segment retainingcoupling or a similarly shaped open retainer coupling having amultiplicity of sections circumferentially disposed to join the abuttingflange end sections of the adjacent pipe sections.

[0077] The invention also comprises a method of forming a flange at theend of a pipe section or fitting having transverse corrugations in whichthe flange is formed from a circumferential portion of the endcorrugation and/or the liner of the pipe at the end of the pipe sectionor fitting.

[0078] In providing a soil tight and/or water tight seal between pipesections, the invention comprises a method of joining abutting sectionsof flanged pipe by providing a section of corrugated plastic pipe and arigid plastic or metal pipe or fitting having a flange at its end,inserting a gasket between or around the two flanges, andcircumferentially clamping the flanges to provide pressure on theexterior surface flanges to draw them together and thereby compress thegasket. A peripheral flange clamp having a single segment or amultiplicity of segments joins the flanged ends and provides compressionof the gasket when a gasket is used. The method further involves forminga flange at the end of a section of corrugated plastic pipe bytransversely severing a section of the corrugated pipe at an axiallocation of a pipe end corrugation.

[0079] The invention is also a kit for providing a water tight sealbetween adjacent sections of corrugated plastic pipe or a section ofcorrugated plastic pipe and a pipe or fitting having a flanged end. Thekit comprises a gasket and a circular flange clamp having an initialopening sufficient to receive therein the adjacent flanges of the pipesections to be joined; the clamp compresses the gasket between theflanges. For the on site fabrication of joints between corrugated pipesections and another flanged component, the kit of the inventionincludes a portable router or saw and guide fixture assembly for makingfield cuts in a section of corrugated pipe and/or fabricated fittings.The router or saw provides a flange at the pipe or fitting end bycutting away a circumferential portion of a pipe corrugation or liner toform the flange from the remaining section of the corrugation.

[0080]FIG. 1 shows the preferred embodiment for two sections of dualwall corrugated plastic pipe 1 each having a flange 2 at its end formedfrom a circumferential portion of a corrugation. FIG. 2 shows thepreferred embodiment for a single wall corrugated plastic pipe 3 at itsend having a flange 2 formed from a circumferential portion of acorrugation. FIG. 3 shows another embodiment for sections of dual wallcorrugated plastic pipe 1 having a flange 2 at its end formed from acircumferential portion of the liner 4. FIG. 4 shows a dual wallcorrugated plastic pipe 1 having a flange 2 at its end formed from acircumferential portion of the liner 4 and a portion of a corrugation.

[0081] In the invention, a corrugated pipe with a design having a flangeformed from a circumferential segment of the end corrugation, from theliner at the end of the pipe or from a circumferential segment of an endcorrugation and the liner is provided. The method of fabricating flangedends on plastic pipe with transverse corrugations can be accomplished inthe factory and in the field by cutting the pipe at a corrugation sothat a flange shaped portion of the end corrugation remains. In thefield, the contractor can cut the corrugated pipe and form the flangesimultaneously by using a portable router or other cutting devices suchas a circular saw having a fixture that guides the cutter around thecircumference of the pipe at the desired axial position. While theapplication herein refers to the pipe and joint elements as “circular,”it is noted that the large diameter pipes with which the invention isintended to be used may have other cross sections, such as elliptical,oval and the like and it is intended to include such cross sections aswell within the scope of the term “circular.” FIGS. 20A and 20Billustrate such pipes and joints.

[0082] The invention also provides a design and method for water tightjoining of plastic pipe having transverse corrugations. FIG. 5A shows asoil tight and water tight joint design for dual wall pipe havingtransverse corrugations. This joint comprises a section of dual wallplastic pipe 1 having transverse corrugations and a flange 2 formed fromthe circumferential section of the end corrugation, a wedged shapedgasket 16 inserted between to abutting flanges and a “V” retainingcircular flange clamp 6. FIG. 5B shows a soil tight and water tightjoint for two abutting dual wall corrugated plastic pipe sections havingflange ends 2, an “O” ring gasket 7 between the abutting flanges and asingle segment “V” retaining circular flange clamp 9. FIG. 5C shows asoil tight and water tight joint between a dual wall corrugated plasticpipe having a flange end and a rigid pipe 10 end also having a flangeend. This embodiment demonstrates how metal and rigid plastic pipe ends10 can be joined with a flat gasket 5 and a multi segmented “V”retaining circular flange clamp 9. FIG. 5D exhibits an embodiment thatshows how the method and design shown in FIG. 5C can be applied to joincorrugated plastic pipe to concrete pipe 11 by using a metal pipesection 12 that is fixed to the concrete pipe by mortar. FIG. 5Eexhibits an embodiment in which two abutting dual wall corrugated pipeflange ends are joined by an “inverted wedge” circular flange clampcompressing an “O” ring gasket. FIG. 6A shows soil tight and water tightjoining of two sections of dual wall corrugated plastic pipe 1. In thisembodiment, circular flange clamp 14 has two split annular plates and anexternal reverse “V” gasket 13. FIG. 6B shows the soil tight and watertight joint embodiment wherein circular clamp 14 is utilized to compressthe flat gasket 5. FIG. 7A and 7B show respectively a front and sideview of an annular flat gasket 5 preferably fabricated from across-linked elastomer or rubber. FIG. 7C and 7D show respectively afront and side view of a wedge shaped gasket 16. Many shapes aresuitable for this application; an example is the “O” ring 7 shown inFIGS. 7E and 7F . Some categories of gaskets, however, have rounded,elliptical, or other cross-sections that are intended herein to beincluded within the definition of “O” ring gaskets. FIGS. 7G and 7Hrespectfully shows a front and side view of an external gasket 13 havingan inverted “V” cross-section. The external gasket straddles the outsideof the flanges 2. FIG. 8A and 8B are front and sides views that show atypical circular flange clamp 6 sometimes referred to as a “V” retainingcoupling. The function of this flange clamp 6 is to draw the flangestogether as the diameter of the clamp is made smaller by the action ofclosing a clamp or a tightening a bolt 18. The “V” shaped circularchannel 17 provides a dual wall tapered clamping action that compressesthe gasket between the flanges. The material of construction of the “V”retaining coupling can include a rigid plastic or metal. The preferredembodiment utilizes a stainless steel similar to 301, 303 and 304stainless steel to minimize corrosion, however, galvanized steel orrigid plastic construction is adequate and may be more cost effectivethan stainless steel. 316 stainless steel is utilized for marineapplications where salt water is a concern. The “V,” “U,” inverted wedgeor other open shaped groove, slot, or receptacle of the peripheralflange clamp may be formed from a single segment or multiple segments.Multi-segmented “V” retaining couplers provide more convenient assemblyby making the circular flange clamp 9 more flexible. Preferably, theperimeter clamp should have sufficient hoop flexibility to accommodatethe change in shape or roundness caused by back filling. The clampshould allow a resiliency comparable to that of the pipe to accommodateexpansion and contraction, and compression of the pipe when it isburied. FIGS. 8C and 8D respectively show a front and side view of a “V”retaining circular flange clamp 9 with three segments. The tri-segmentedcircular flange clamp 9 is preferred to single, dual and quad segmentedclamps; however, all are satisfactory. FIGS. 8E and 8F respectively showa front and side view of a tri-segmented, “inverted wedge” shapedcircular flange clamp. FIGS. 9A and 9B respectively show front and sideviews of an alternate circular flange clamp 14 having two split annularplates that are brought axially together to compress the gasket.

[0083] There have been many attempts to utilize larger circular flangetype clamps to draw the full end corrugations together and simultaneouscompress a gasket. These attempts fail because of the flexibility of thecorrugations. The corrugations readily deform under pressure and moveout of the way when water pressure is applied. Efforts are being made tostiffen the corrugations by injecting them with rigid foam to improvethe joint properties. The structural advantage of the present inventionis that the circular flange clamp does not rely on the stiffness of theplastic. Instead the plastic is subjected to compression by the circularflange clamp and transfers this stress into the gasket. Thestress-cracking behavior of the pipe is not significantly affectedbecause there are little or no tensile stresses applied to the plasticflange.

[0084]FIGS. 8I and 8J show a ratchet style flange clamp 17. Theadvantage of ratchet type flange clamps are that they offer a convenientway of making a connection between the ends of the cylindrical band 18initially and sub sequentially closing the gap between the ends of thecylindrical band 18. This clamp has two straps 65 that are attached toone end of the periphery of cylindrical band 18 and having radiallyinward projection on the other. A series of holes in the cylindricalband 18 provide a means of interlocking the inward radial projections onstraps 65. The tightening of the clamp in this case is accomplished byand external lever mechanism 64 that increases the over lap of straps 65and cylindrical band 18 causing the radial inward projection to ratchettighter by interlocking with a hole further from the ends of cylindricalband 18. There are a multitude of ratchet mechanisms some that utilizeexternal straps or wire, integral toggle mechanisms, some with radialoutward and/or axial projections and others. The example shown in FIGS.81 and 8J is intended to demonstrate that flange clamps having ratchetmechanisms represent embodiments to this disclosure.

EXAMPLE I

[0085] An example of the preferred embodiment is the forming of watertight joints with High Density Polyethylene (HDPE) pipe utilized fordrainage and sanitary sewer applications. The circular flange clamp is a“V” retaining coupling fabricated from 301 Stainless Steel and thegasket is extruded and spliced from natural rubber, polyisobutylene orneoprene rubber. In this example, the corrugated HDPE pipe hascorrugations that are too flexible to maintain the gasket compressionrequired for water tight sealing. As a result, typically, thecorrugations are filled with rigid foam to provide sufficient stiffness.The process of foaming the corrugations is time consuming and relativelyexpensive. The present invention eliminates stiffening requirementsbecause the rigid clamp provides the stiffness. In this preferredembodiment the wedged shaped gasket may be a cured natural rubber orpolyisobutylene having a durometer or hardness on the Shore A scalebetween 45 and 60. However, a variety of elastomeric gaskets havingsimilar properties will also function well.

[0086]FIGS. 10A, 10B and 10C and FIGS. 10D, 10E and 10F show theconstruction of a soil tight and water tight joint between two sectionsof dual wall corrugated plastic pipe 1 with flange ends formed from acircumferential portion of the end corrugations. This joining isaccomplished by inserting a wedge shaped gasket 16 and wedged shapedgasket 61 having a contour that matches the interior surface of flange 2between abutting flange ends of the dual wall corrugated plastic pipeand squeezing the gasket with the circular flange clamp 6. In thispreferred embodiment, the flange clamp and gasket is designed so thatthe gasket compresses between 5% and 30% when clamp is closed. Thegasket compression may vary depending on the durometer of the gasket andthe water tight pressure limit required. The preferred configurationutilizing 10% compression of a 45 Shore A durometer typically testswater tight as per ASTM 3212 to pressures that exceed 30 pounds persquare inch. The pressure limit specified in ASTM 3212 is 10.8 psi. Theminimal wetted area of the gasket minimizes the hydraulic effect thattends to separate the pipe under internal pressure and the rigidity ofthe flange clamp locks pipe ends together thereby preventing jointseparation normally a result ground shifts, seismic anomalies andimproper back fill. The invention also provides the capability ofdesigning the flange clamp so that the clamp system provides a pressurerelief function to protect the pipe from transient internal pressuresurges that reach a predetermined level that requires relief. This isaccomplished in pipes of predetermined size by reducing the stiffness ofthe radial walls of the clamp sufficiently to provide a leakage at apre-selected internal pressure.

EXAMPLE II

[0087] In this second example, the method and design of soil-tight andwater tight joining of single wall corrugated plastic pipe isdemonstrated for a second time. FIG. 11A shows two sections of singlewall corrugated plastic pipe 3 with a flange 2 formed by acircumferential portion of an end corrugation. FIG. 11B shows thecomponents for fabricating a water tight joint; the single wall plasticpipe 3 with flange 2, the flat gasket 5 and the circular flange clamp 6in the open position. FIG. 11C shows the assembled joint wherein thecircular flange clamp 6 is closed causing the gasket 5 to compress.Flange 2 is in compression avoiding tensile stresses that enhance stresscracking.

EXAMPLE III

[0088] This example shows an alternate means of applying the disclosedinvention to the water tight joining of dual wall corrugated plasticpipe. FIG. 12A shows two sections of dual wall plastic pipe 1 havingtransverse corrugations and flanges 2 at the pipe end formed from theliner. FIG. 12B shows the components for fabricating a water tightjoint; the dual wall plastic pipe 1 with flange 2 formed from the liner4, the flat gasket 5 and the circular flange clamp 6 in the openposition. FIG. 12C shows the assembled joint wherein the circular flangeclamp 9 is closed causing the gasket 5 to compress.

EXAMPLE IV

[0089] This fourth example demonstrates the method of applying theinvention disclosure to dual wall corrugated plastic pipe 1 having aflange 2 at its end formed by both the liner 4 and the corrugation asshown in FIG. 13A. FIG. 13B shows the components for fabricating a soiltight and water tight joint; the dual wall plastic pipe 1 with flange 2,a wedge shaped gasket 7 and the circular flange clamp 9.

EXAMPLE V

[0090] The fifth example demonstrates in FIGS. 14A, 14B and 14C, themethod of applying the invention disclosure to dual wall corrugatedplastic pipe 1 having a flange end 2, an “O” ring gasket 7 and circularclamp 6.

EXAMPLE VI

[0091] The sixth example demonstrates in FIGS. 15A, 15B and 15C, themethod of soil tight and water tight joining of sections of dual wallcorrugated plastic pipe 1 by compressing an external gasket 13 thatstraddles the flange ends 2 and is compressed by circular flange clamp6.

EXAMPLE VII

[0092]FIG. 16A represents an embodiment of this invention wherein dualwall corrugated plastic fabricated “Y” fitting are joined to sections ofdual wall corrugated plastic pipe by inserting a gasket 5 between theend flanges and by utilizing circular flange clamps 9. Although thisembodiment is portrayed by using a “Y” fitting, the invention can beapplied equally well to most fittings including but not limited to “T”,4 way, elbows and angle fittings.

EXAMPLE VIII

[0093]FIGS. 16B and 16C respectively show front and side views of anembodiment of this invention wherein a molded in-line reducing “T”fitting 37 fitting that couples two sections of dual wall corrugatedplastic pipe 1 and an integral, stepped, off-set, selectable pipe size,reducer coupling 38 to a corrugated plastic pipe 41 having the same orsmaller pipe size as the corrugated plastic pipe 1. All joints arecomprised of a gasket between the end flanges that are sealed bycircular flange clamps 9 as depicted in FIGS. 5A, 5B and 5C. This designis unique in the fact that it discloses an integral, off-set, selectablesize, reducer coupling 38 for soil and water tight joining of dual wallcorrugated plastic pipe. The integral reducer coupling comprises aseries of flange diameters wherein the flange diameter of choice isselected by cutting the reducer coupling 38 at the plane that matchesthe size requirement. In this example the reducer coupling was cut atplane 30. A field cut at plane 31 and 32 offer larger diameterpossibilities. Please note that the axes of the reduced fitting optionsare off set so that the drainage into and out of the pipe will always beat the bottom or top of the pipe. The integral selectable reducercoupling 38 need not be offset and the selectable reducing diameterscould be concentric. This invention has the advantage that the pipemanufacturer need only produce one universal fitting wherein thecustomer can field select the reduced pipe size by simply cutting offthe stepped reducer coupling at the desired flange diameter.

EXAMPLE IX

[0094]FIGS. 16D and 16E respectively show front and side views of anembodiment of this invention wherein a molded selectable diameter,stepped off-set reducer coupling 40 is utilized to join a fabricatedin-line reducing “T” fitting to two corrugated plastic pipe sections 1and a section of dual wall corrugated plastic pipe 41 having a flangediameter smaller than the connecting fitting. This is accomplished byinserting a gasket between the end flanges and by utilizing circularflange clamps 9 as indicated previous in FIGS. 5A, 5B and 5C. Thisdesign is unique in the fact that it discloses a design and method forjoining standard fabricated fitting to corrugated flange end plasticpipe sections by means of a molded selectable size, off-set reducercoupling. The selectable size feature is achievable by cutting thereducer at the plane that matches the size requirement. In this examplethe reducer was cut at plane 35. A field cut at plane 36 offers a largerdiameter possibility. Please note that the axes of the reduced fittingoptions are off set so that the drainage into and out of the pipe willalways be at the bottom or top of the pipe. This invention has theadvantage that the pipe manufacturer need only produce one size diameterfor each fitting type and provide a molded selectable stepped offsetreducer coupling that the customer can field cut to select the properpipe size.

EXAMPLE X

[0095]FIGS. 10G, 10H and 10I show a bell and spigot embodiment of thisinvention. FIG. 10G shows dual wall corrugated plastic pipe 1, wedgedshaped gasket having a contour that matches the internal surface offlanges 2 and flange clamp bell 62 and flange clamp spigot 63. FIG. 10Hshows the joint partially assembled wherein the flange clamp bell 62 isexpanded as it passes over flange clamp spigot 63. Flange clamp bell hasaxially slots cut into its outer circumferential protrusion (not shownin the FIG. 10G, 10H and 10I) that permit the bell to expand in a flatspring like manner. FIG. 10I show the fully assembled flange clamp belland spigot joint whereby the flat spring fingers of flange clamp bell 62contract inward to lock in place flange clamp spigot 63 and sustaincompression of wedged shaped gasket 61. This embodiment although morecomplex and costly demonstrates how the invention provides the axialcompression of the gasket and rigidity of the coupling and still can beassembled in the manner similar to the bell and spigot joints usingradial compressed gaskets.

[0096] A kit shown in FIG. 17 is used in the field to provide a jointbetween adjacent sections of corrugated plastic pipe 1 or a section ofcorrugated plastic pipe having essentially similar cross-sections and apipe or fitting having a flanged end. The kit includes a gasket 5 havinga cross-sectional shape in a correspondence with the sections to bejoined and a circular flange clamp having a cross sectional shape suchthat the clamp 9 is capable of straddling the flanges at the endsections to be joined. FIG. 18 shows a kit that includes a portablerouter, saw, or other suitable cutting device 20 and guide fixture 21for making field cuts in the end section of the corrugated pipe toprovide a flange at the end thereof by forming a radially extendingcircumferential portion of a section of a corrugation or the liner ofthe corrugated pipe.

INDUSTRIAL APPLICABILITY

[0097] The manner in which the invention is capable of exploitation inindustry and the way in which the invention can be made and used areevident from the foregoing description and the nature of the invention.A new and improved corrugated polyethylene pipe, and a joint and joiningmethod, system, and kit therefor is provided that is useful in drainage,agriculture, highway, sanitary sewer, waste water reuse, irrigation,industrial waste, animal waste and fiber optics, utility cable, andother pipe based applications.

[0098] Having thus described the invention in detail, those skilled inthe art will appreciate that, given the present disclosure;modifications may be made to the invention without departing from thespirit of the inventive concept herein described. Rather, it is intendedthat the scope of the invention be determined by the appended claims.

1. A section of a large diameter corrugated plastic pipe havingtransverse corrugations and a flange formed by a circumferential portionof a corrugation radially extending from the end section of the pipe. 2.A section of a large diameter corrugated plastic pipe having transversecorrugations and an inner liner in which a flange is formed by acircumferential portion of the corrugation radially extending from theend section of the pipe.
 3. A section of a large diameter corrugatedplastic pipe having transverse corrugations and an inner liner in whicha flange is formed by a portion of the liner radially extending from theend section of the pipe.
 4. A section of a large diameter corrugatedplastic pipe having transverse corrugations and an inner liner in whicha flange is formed by a circumferential portion of the corrugation insubstantial contact with a portion of the liner radially extending froman end section of the pipe.
 5. Two abutting sections of large diametercorrugated plastic pipe each having transverse corrugations and a flangeintrinsically formed from the pipe material at abutting ends joined inan assembly having a clamp encompassing the abutting flanges and forminga joint.
 6. Two sections of large diameter corrugated plastic pipe eachhaving transverse corrugations and a flange intrinsically formed fromthe pipe material at the end of each pipe section joined in an assemblyin which a gasket is interposed between the flanged ends of the pipe anda peripheral clamp encompasses the abutting flanges.
 7. The pipesections of claim 6 in which the gasket has a flat surface in acorrespondence with the surface of the flange transverse to the axis ofthe pipe facing from the end of a pipe.
 8. The pipe sections of claim 6in which the gasket has an essentially trapezoid shaped transverse crosssection corresponding to the adjacent transverse cross sections of theabutting pipe flanges at the joint.
 9. The pipe section of claim 7 inwhich the gasket includes a wedge shaped section.
 10. The pipe sectionof claim 7 or 8 or 9 in which corners of the gasket are contoured. 11.The pipe section of claim 6 in which the gasket comprises an “O” ringshape in transverse cross section.
 12. The assembly of claim 5 or claim6 in which the peripheral clamp includes an internal channel facingtoward the center of the pipes and straddles the flanges to provide acompressive force.
 13. The assembly of claim 5 or claim 6 in which theperipheral clamp includes facing sections at the opposite sides of theflanges on the pipes to be joined and the clamp provides a compressiveforce between the flange surfaces in the longitudinal direction of thepipe axis.
 14. The assembly of claim 12 in which the clamp comprises oneof an inverted “V” channel and an inverted “U” channel extending arounda section of the flange.
 15. The assembly of claim 12 in which the clampencompasses the flanges and comprises a wedge shape in transverse crosssection having an opening at one end and an extended section at theopposite end in which the open section of the wedge is lesser in lengththan the extended section and faces the center of the pipe with respectto the longitudinal axis of the pipe.
 16. The assembly of claim 12 inwhich the clamp comprises a multiplicity of peripheral sections joinedcircumferentially about the flange.
 17. The assembly of claim 12 inwhich the clamp extends peripherally about the flanges in a singlecircumferential length essentially in correspondence with the nominaldiameter of the pipes joined.
 18. A section of large diameter corrugatedplastic pipe having transverse corrugations and a flange at an endintrinsically formed from the pipe material joined to one of the groupof plastic pipes; non-plastic pipes; plastic fittings; and non-plasticfittings having a flange end at the location of a joint.
 19. The methodof providing a flange at the end of a corrugated plastic pipe sectionhaving transverse corrugations by cutting off a circumferential portionof an end corrugation to provide a remaining section of the corrugationintegrally and radially extending from the end of the pipe as a flange.20. The method of providing a flange at the end of a dual wallcorrugated plastic pipe section having transverse corrugations and aliner by cutting off a circumferential portion of an end corrugation andthe liner to provide a remaining section of the corrugation integrallyand radially extending from the end of the pipe as a flange.
 21. Themethod of claim 19 or claim 20 for forming a flange at the end of acorrugated plastic pipe section having transverse corrugations and aliner including forming a circumferential flange portion integrally andradially extending from the end of the pipe from the liner.
 22. Themethod of joining a section of corrugated pipe plastic having a flangeat its end forming a first member abutting a second member being asection of a corrugated pipe, a non-plastic pipe or a fitting having aflange at its end comprising aligning the first and second members in aco-linear relationship in which the end flanges of the members are in anapproximately abutting relationship, and applying a clampcircumferentially straddling the flanges to provide an axiallycompressive force on the exterior surface of the flanges to draw theflanges together.
 23. The method of claim 22 including inserting agasket between the flanges and compressing the gasket with the forcegenerated by tightening the applied clamp.
 24. Two sections of largediameter corrugated plastic pipe each having transverse corrugations anda flange at the end of each pipe section joined in a clamped assembly inwhich a channel clamp is applied to the radially peripheral ends of theflanges and the clamp exerts a force to compress the gasket between theinner surface of clamp channel and the outer peripheral edges of theflanges.
 25. A kit for providing a joint between adjacent sections ofcorrugated plastic pipe or a section of corrugated plastic pipe havingessentially similar cross-sections and a pipe or fitting having aflanged end, the kit including a peripheral flange clamp having a crosssectional shape such that the clamp is capable of straddling the flangesat the end sections to be joined.
 26. The kit of claim 25 including agasket having a cross-sectional shape in a correspondence with theflanges at the sections to be joined.
 27. The kit of claim 25 includinga portable cutting device and a guide fixture for making field cuts inthe end section of a corrugated pipe to provide a flange at an end ofthe pipe by cutting off a circumferential portion of an end corrugationto provide a remaining section of the corrugation integrally andradially extending from the end of the pipe as a flange.
 28. The methodof forming a flange at the end of a section of corrugated plastic pipeby transversely severing from the pipe a section of a corrugation of thepipe at an axial location on the corrugation at the end of a pipesection.
 29. The method of forming a flange at the end of a section of adual wall corrugated plastic pipe by transversely severing from the endsection of the pipe a section of a corrugation and a section of theliner.
 30. A fitting having at least two flanges in which one of thefitting ends has an off set, selectable diameter flange reducer couplingcapable of being cut off at a predetermined flange diameter.
 31. Thefitting of claim 30 wherein the fitting comprises a molded plasticcomposition.
 32. The fitting of claim 31 wherein the fitting is one ofan in-line, “Y”, “T”, 4 way, elbow or angle.
 33. The assembly of claim 5or claim 6 in which the clamp is one of a toggle clamp, a ratchet clampand a screw clamp.
 34. The assembly of claim 6 in which the clampcomprises an interlocking assembly of mating components seated withinthe recess of a corrugation at each pipe end and straddling the flanges,the components interlocking upon the exertion of an axial force upon thepipe sections in the longitudinal direction of the pipe and compressingthe gasket interposed between the flanges.
 35. The assembly of claim 6providing a predetermined pressure relief in which the stiffness theradial walls of the clamp is predetermined at a sufficiently low measureto provide a leakage at the joint at a pre-selected internal pressure.